Method and apparatus for filling receptacles



c. F. CARTER 2,799,465

METHOD AND APPARATUS FOR FILLING RECEPTACLES July 16, 1957 5Sheets-Sheet 1 Filed Feb. 28, 1955 INVENI'OR Ulwmzwel? Carha" ATTORNEYSy 1957 c. F. CARTER 2,799,465

' METHOD AND APPARATUS FOR FILLING RECEPTACLES Filed Feb. 28, 1955 5Sheets-Sheet 2 A9 43A .25 LL as l 3 f0 ATMOSPHERE on. cam/em CarterATTORNEYS c. F. CARTER 2,799,465

METHOD AND APPARATUS FOR FILLING .RECEPTACLES July 16, 1957 5Sheets-Sheet 5 Filed Feb. 28, 1955 INVENTOR ATTORNEYS July 16, 1957 c.F. CARTER 2,799,

METHOD AND APPARATUS FOR FILLING RECEPTAQEES Filed Feb. 28, 1955 V 5Sheets-Sheet 4 INVENTOR LZfiremefi! Carier BY mAAw Am ATTORNEYS2,799,4fi Patented July 16, 195? METHOD AND APPARATUS FOR FILLINGRECEPTACLES Clarence F. Carter, Danville, iii. Application February 28,1955, SerialNo. 4%,942

16 Claims. c1. 249-62) This invention relates generally to a method offilling receptacles particularly adapted for use where very finelydivided material is involved and to a filling machine particularlyadapted for dispensing such finely divided material into receptaclessuch as valve type bags. More specifically, as set forth hereinafter,the invention is directed to an automatic bag filling machine whichemploys a reduced pressure or vacuum within a bag enclosing shroud todraw finely divided material into the bag and, further, to a method offilling receptacles in a series of increments with very finely dividedmaterial to produce highly compacted material as the final product.

Through the years a variety of different filling methods and machinesfor filling receptacles have been developed and have to varying degreesmet with satisfactory accep-;

fluffy by reason of air entrained between the powder par-j ticles.Whereas such entrained air may serve a useful purpose in facilitatingfreer flow of the material through the dispensing machine to thereceptacle being filled, it is a distinct drawback from the standpointof achieving the desired degree of material compacting within the filledreceptacle. Removing this entrained air and thereby compacting thematerial presents a real problem in filling the receptacle with thesepowdered materials.

In the past, one suggested solution to compacting finely dividedmaterial by freeing it of air which becomes entrained between the powderparticles has been to subject the receptacle during filling to rapidvibration. Under this filling method, as the particles tend to settledown, material is added to the receptacle until the receptacle containsthe desired weight of material for its particular size. ently beingused, it has a distinct disadvantage in that it may require a period ofseveral hours of continuous receptacle vibration and repeated materialadditions to fill a drum with the desired weight of powdered material asfor example in the case where silica gel or carbon black is beingdispensed. In comparison with this length of time required for vibratoryfilling, the filling method of the instant invention can achieve thesame degree of material compacting in filling the same size drum in amatter of one minute.

As a further problem encountered in the handling and dispensing of veryfinely divided powders, the characteristic of such powders to becomedispersed in the atmos- Whereas this filling method has been andispresphere surrounding the filling machine and thereafter settle on themachine parts and areas adjacent the machine has been recognized as adefinite problem in the development of filling machines. Accordingly, itis of the utmost importance that a filling machine for use in handlingsuch finely divided powders be constructed to reduce to a minimum theescape of powders either from the machine mechanism itself or from thereceptacle as it is being filled. The construction of the fillingmachine of the instant invention and its mode of operation have beendeveloped to possess the required characteristics for the handling offinely divided powders. As a further advantage of the filling machinedescribed in detail hereinafter, its automatic operation, commencingfrom the time of introduction of the bag to be filled into the shroudand continuing through the completion of the bag filling cycle,contributes to reducing the chance for escape of powdered material intothe surrounding atmosphere.

It is a primary object of the instant invention to provide a method offilling receptacles with finely divided materials or powders, whichmethod requires a minimum of time in the filling operation and producesa high degree of compacting of the material dispensed into thereceptacle.

A further object of this invention is to provide a method of fillingreceptacles under vacuum in a series of increments wherein the vacuumwhich is effective to draw the material into the receptacle andsimultaneously assist in withdrawing entrained air from the material ismomentarily decreased between each increment of fill dispensed into thereceptacle to permit an instantaneous reverse flow of air back into thereceptacle while continuing to withdraw entrained air from the powderedmaterial mass.

It is also a principal object of this invention to provide a bag fillingmachine having a shroud providing a chamber for enclosing the bag beingfilled to subject the bag exterior to a reduced pressure and furtherhaving a filling spout with a seal element actuatable to retain the bagon the spout so as to preclude seepage of powdered material from the baginterior during filling.

It is an additional object of the instant invention to provide a fillingmachine having .a shroud suspended from a scale mechanism and providinga chamber for receiving the bags being filled, together with valves forcontrolling vacuum imparted to the shroud chamber, venting the baginterior, powdered material flow and relief to atmospheric pressure ofthe shroud interior, all actuatable in proper sequence to effectincremental filling of the bag.

Other and more specific objects, features and advantages of the instantinvention will be apparent from the detailed description set forthhereinbelow. Such description given in connection with the accompanyingdrawings which form a part of this application is illustrative merely byWay of example of a preferred form of the invention. It will also beappreciated that the method of the instant invention may be practiced inusing a variety of different structures other than that specificallyillustrated in this application. Accordingly, the invention consists ofsuch novel method features, arrangements and combinations of parts asmay be shown and described in connection with the apparatus herein setforth.

In the drawings:

Figure l is a front elevational view of a bag filling machineincorporating the features of the instant invention; Figure 2 is a sideelevational view of the machine of Figure l;

- Figure 3 is a sectional view taken on line 33 of Figure 2;

Figure 4 is a detailed section of its related parts;

the filling spout and the side wall of shroud 40.

Figure 5 is a sectional view taken on line 55 of Figure 4; and

Figure 6 is a schematic view of the circuitry employed in the automaticoperation of the bag filling machine.

Referring specifically to the overall views of the bag filling machineas shown on Figures 1 and 2, such machine includes a support frame 10having upright legs 11 interconnected by a plurality of transversemembers 12. A scale mechanism 13 is suspended from one of the uppertransverse members 12. This mechanism consists of a primary scale beam14 fulcrumed at one end on a rod 15, which rod in turn is suspended bymeans of parallel cables 16 from a bar 17 which extends across thesupporting transverse member. To facilitate proper vertical location ofthe fulcrum for beam 14 a turn buckle 18 is interposed in each of thecables 16.

The opposite end of primary scale beam 14 is interconnected with one endof a secondary scale beam 19 by means of a pair of cables 20 engagingwith pins 21 carried in the adjacent overlying ends of beams 14 and 19.The secondary scale beam 19 is fulcrumed on a rod 22 which is suspendedfrom the upper-transverse member by means of a cable 23 connectedbetween the rod and such member.

The secondary scale beam 19 overlies beam 14 with the end thereofopposite pin 21 extending between cables 16 and carrying a threaded rod25 having a counterweight 26. It will be appreciated that adjustment ofcounterweight 26 by threading it along rod 25 will be effective to alterthe response characteristics of the scale so that such mechanism may beadjusted to respond to different total weights of material dispensedinto the bags being filled.

Adjacent threaded rod 25 and extending upwards from the end of scalebeam 19 there is provided a pin 27 having a stud 2S threaded into itsupper end to engage with the actuator of an electric switch WS. Thisswitch contains a pair of normally closed contacts. Upon actuation ofthe scale mechanism in response to material dispensed into thereceptacle being filled, the pin 27 and its stud 28 will be movedupwardly as carried by beam 19 to effect opening of switch WS.

To limit movement of the secondary scale beam 19, a pair of studs 30 aremounted respectively above and below the beam end. These studs arethreaded into their supports, each preferably with a locking nutprovided thereon, so that adjustment as to the possible range ofmovement of the beam 19 may be made. Also coupled with the outer end ofbeam 19 is a dash pot device 31. This device, secured on the skeletonframe lth'has its shaft 32 connected to the outer end of beam 19 so asto retard movements of the beam as the material is dispensed into thereceptacle being filled. Thus, the dash pot device tends to overcome thepossibility of the scale mechanism partaking of undesirable rapidmovement which might prematurely effect opening of the switch W8.

A shroud 40 is suspended from the scale mechanism 13 by means of a cable41 connected medially of the ends of primary scale beam 1 by a pin 42.Cable 41 has a turn buckle 43 interposed therein to facilitateadjustment of the position of shroud 40 relative to the scale mechanism.The cable 41 is coupled at its lower end to a pin 44. The pin 44 engagesbeneath one leg of an angle 45 while the other leg of such angle isrigidly secured to As shown more clearly in the sectional view of Figure3, the shroud 40 provides a generally rectangular interior 53 supportedlongitudinally of and adjacent one corner of the shroud by means ofhinge ears 54 and 55, carried respectively by the shroud 40 and door 52.

The hinge cars 55, midway of the length of shroud door 52, extendrearwardly of the door pivot to provide an arm 56. Supported on theshroud adjacent the arm 56 is a pneumatic actuator 57 having theactuating rod thereof pivotally connected to the arm 56 with thecylinder of such actuator pivotally supported on the shroud. It will bereadily appreciated that by appropriately directing pressurized fluid tothe actuator 57, the door 52 will be opened or closed accordingly. Toseal the joint between door 52 and shroud 40, there is provided aflexible seal strip 60 which is secured along the edge of the shroud bymeans of a metal strip 61.

As shown on Figure 2 an electric switch DS is mounted on frame 10 withits actuator positioned so as to be engaged by arm 56 when the door isin its closed position. The contacts of switch D8 are normally open andtherefore such switch contacts are closed only when the door 52 isclosed under control of the pneumatic actuator 57.

To restrict lateral sway of the shroud 40 while permitting freeunrestricted longitudinal movement of the shroud under the yieldingmovements of the scale mechanism, there are provided a series offlexible cables connected between the support frame and the shroud.Thus, cables and 66 are connected between elements secured respectivelyto the lower forward end of the shroud 40 and support frame 10.Likewise, the rear lower end of shroud 40 is restrained by flexiblecables 68 connected to the bottom of the shroud and the transversemembers on opposite sides of the shroud. To restrain backward andforward movement of the shroud, flexible cables 70 and 71 are connectedto elements carried respectively by the lower rear end of the shroud andone of the lower transverse members. Similar restraining cables at theupper rear corner of the shroud are provided in the form of cables 74and 75 to restrain side to side sway and cables 77 and 78 to restrainback and forth movement of the upper end of the shroud. It will beappreciated that a limited amount of slack in all thehereinabove-mentioned anti-sway cables is provided so as to permitlimited up and down movement of the shroud as the scale mechanismresponds to the material dispensed into the bag being filled.

A pair of parallel members 80 and 81 are mounted interiorly of and atthe upper end of the shroud with member 80 being rigidly secured to theshroud 40 and member 81 being secured to and carried by the shroud door52. Likewise, a pair of parallel members 83 and 84 are provided adjacentthe lower end of the shroud interior with member 83 being secured to theshroud and member 84 being mounted on and carried by the shroud door 52.In the closed position of door 52 the pairs of parallel members arepositioned as shown in Figure 1 so as to leave a space extendinglongitudinally between each pair to receive the respective upper andlower seams of the bag being filled. These members are grooved so as topromote application of vacuum to the entire exterior surface of the bagbeing filled.

It will be noted that the members 83 and 84 have a comparatively largeheight, substantially greater than the width of the seam of the bagwhich will be inserted between them. The size of these two'members maybe 65' varied as desired to accommodate bags of different lengths.

Thus, for example, where bags substantially as long as the shroud 40 arebeing filled,.the members '83 and 84 would be substantially shorter toprovide an'open space above such memberswithin the shroud which willaccommodate such a long bag' during the filling operation. Thus,'-it isa simple matter to appropriately vary the size of members 83 and 84toadapt the bag filling machine of the instant invention to the handlingof bags of different overall length.

A relief valve is provided mounted in the rear wall of the shroud 40 tocontrol communication of the shroud averages interior with atmosphericpressure. As shown, this valve is of the diaphragm type wherein openingand closing of such valve is effected by regulating the flow ofpressurized fluid to one side of a diaphragm within the valve. Thetiming of the opening and closing of relief valve 90 will be describedin more detail with regard to the description of the schematic diagramof Figure 6.

A vacuum control valve 95 is mounted in the upper wall of the shroud 40and controls communication of the shroud with a source of vacuum or lowpressure through a conduit 96. As part of the conduit 96 there areflexible sleeve sections 97 which permit relative movement betweenshroud 40 and the frame as the scale mechanism responds to the weight ofmaterial dispensed into the bag being filled. As in the case of reliefvalve 90, valve 95 is shown as being of the diaphragm type and itsactuation is effected by appropriate control of a pressurized fluidadmitted to such valve.

As shown more clearly in Figure 4, the shroud 40 is provided adjacentthe rear upper corner thereof with a housing 100 which serves to mountthe filling spout 101 that extends inwardly of the shroud interior. Itwill be appreciated that the bag to be filled when positioned forfilling will have the filling spout extending through the bag mouth. Thespout 101 consists of a main tubular member 102 having a flange 103bolted to housing 100 by bolts 104. A pair of seal elements 105 and 106are carried on the periphery of tubular member 102. Each of these sealelements includes a flexible resilient sleeve enclosing a ring whichserves to support the resilient sleeve and hold it in position on thefilling spout. A spacing tube 110 is disposed between the seal elements105 and 106 and a ring 111 provided in engagement with the outer end ofseal element 106. The seal elements, spacing tube and ring are held onmember 102 against the shoulder on such tubular member by a spout tip112 threaded on to the outer end of tubular member 102.

The tubular member 102 of the filling spout is provided with alongitudinal bore 115 communicating at its opposite ends with sealelement 105 and a conduit 116 for the admission of pressurized fluid tothe seal. A similar longitudinal bore 117 is provided in tubular member102 and communicates at its opposite ends with the interior of sealelement 106 and a conduit 118 for the admission of pressurized fluid tothis seal. The regulation and control of the admission of pressurizedfluid to the respective seal elements 105 and 106 is explained .in moredetail hereinafter in connection with the description of Figure 6. As toseal element 105, it will be appreciated that within the scope of theinstant invention the seal may be disposed in the wall of cavity 120 toexpand into contact with the exterior of the spout instead of as shownon the drawing.

Generally, seals 105 and 106 perform the function of retaining the mouthof the bag being filled in proper cooperation with the filling spout.Figure 4 illustrates in section the relationship of a bag B and itsmouth M to the filling spout when the bag is properly positioned forfilling. Such figure also shows, with regard to seal elements 105 and106, the expanded relation of such elements in dotted lines, thusillustrating how the respective seals cooperate with the bag mouth M.

Attention is called to the fact that the seal element 105 is disposedwithin an annular cavity 120 formed within the housing 100. Thus, whenthe bag to be filled is properly positioned within the shroud the valvemouth therein will extend into the cavity 120 so that upon the expansionof seal 105 by the introduction of pressurized fluid thereinto the outerend of the bag mouth will be rigidly clamped and held in engagement withthe outer wall of cavity 120. On the other hand, seal element 106 beingdisposed toward the outer end of the filling spout will engage with thebag mouth at a point where such mouth is not backed up or supported.Accordingly, it is contemplated that normally a lesser pressure willbeapplied to expand seal element 106 than that applied to seal element 105since undue pressure and therefore excessive expansion of seal element106 might result in tearing the tubular bag mouth M.

The housing also provides an upstanding pocket 121 which communicates atits lower end with the annular cavity 120. This pocket receives theupper bag seam as the bag is slid on to the filling spout for thefilling operation. An expandable resilient tube seal 122 is provided ina groove 123 formed in the top and side walls of pocket121. It will beappreciated that upon the admission of pressurized fluid to seal 122 theexpansion thereof will effect clamping of the upstanding top bag seam toassist seal elements and 106 in retaining the bag in position on thefilling spout and also to preclude escape of material from the bag as itis discharged thereinto through spout 101.

It will be noted that a plurality of openings 125 are provided extendingoutwardly from the cavity 120 to communicate with the atmosphereexterior of the shroud. By providing .such openings the high vacuumwithin the shroud, exterior of the bag being filled, will not tend todraw material from the bag outwardly through the bag mouth M past sealelements 105 and 106. Instead the shroud vacuum and the presence of alow pressure within the bag results in any flow of air past the sealelements passing into the bag, thus precluding the escape of thepowdered material into the shroud or atmosphere surrounding the fillingmachine.

The filling spout 101 through its tubular member 102 is connected to amaterial supply conduit 130. As in the case of the vacuum conduit 06,material supply conduit includes a pair of flexible sleeves 131 topermit relative movement between the shroud and the stationary end ofconduit 130. A material supply hopper 132 is coupled to the outer end ofconduit 130 with a material valve 133 interposed between the bottom ofthe hopper and conduit 130. Also connected with conduit 130 is a ventvalve 134 which, as will appea r from the description given below,functions to admit gaseous fluid into conduit 130 and thence into thebag being filled through the filling spout to effect initial opening ofthe bag for receipt of the material. As illustrated, valves 133 and 134are of the diaphragm type wherein opening and closing is effected byregulation of the admission of a pressurized fluid to one side of thevalves diaphragm.

A manually operated three-way valve 135 is shown on Figure 2, disposedin the line leading to vent valve 134. This valve is manually operatedto connect either a pressure source or atmospheric pressure with theinlet to vent valve 134. Thus, when it is desired to open the bag to befilled as mounted within the shroud, valve 135 may be set to communicateatmospheric pressure to vent valve 134 and the vacuum created within theshroud, exteriorly of the bag, used to draw open such bag. On the otherhand, if it be desired to employ positive bag opening pressure, valve135 may be adjusted to communicate the pressure source with the inlet tovalve 134 so that the bag within the shroud will be opened byapplication of positive pressure to the interior thereof.

Having described in detail the structural features of the instantinvention as shown in the embodiment of the drawings, reference will nowbe had to the schematic diagram of Figure 6 which illustrates the mannerin which automatic operation of the filling machine is secured. in thisfigure the leads from the power source as, for example, a 110 volt, 60cycle alternating current source are designated at L-1 and L2. Aspreviously described, the contacts of the weight switch WS are normallyclosed and are not opened until such time as the weight of the materialwithin a bag being filled causes the scale mechanism 13 to respond sothat its pin 27 causes opening of the weight switch. The weight switchcontacts designated WS are shown normally closed. On Figure 6 theremaining contacts of the various relays and of door switch DS are shownin their open state as they exist prior to commencing of an automaticbag filling c cle.

A start push button 150 which is normally open and a normally closedstop button 151 are connected in series with the contacts WS and thecoil of a relay RA. Contacts RAl of relay RA are connected in shuntacross start button 150 so as to form a holding circuit for relay RA,once the contacts of push button 150have been momentarily closed toenergize the relay. Contacts RAz of relay RA are connected across theleads of the power source in series with contacts WS and the coils ofsolenoids SA, SB, SC, and SD. Thus, upon closing of contacts RAz thesolenoids will be energized through contacts WS.

The solenoids SA and SB are connected to actuate separate 3-way valveswhich are operable to couple alternatively pressurized fluid oratmospheric pressure with the pneumatic door actuator 57. As describedabove, door actuator 57 is connected to effect opening and closing ofthe shroud door 52. In the relation shown on Figure 6, the valvescontrolled by solenoids SA and SB are disposed to retain the dooractuator in its position for the door 52 to be fully opened. Uponenergization of solenoids SA and SB, the valves controlled thereby aremoved to couple pressure to the left side of the actuator piston andvent the right side of such piston, as shown on Figure 6, to atmosphere.Such action will cause the actuator to effect closing of door 52.

Solenoids SC and SD are connected to actuate 3-way valves so as toeither admit pressure to the filling spout seals 105, 106 and 122 or toconnect such seals with vacuum and thereby release the seals from theirclamping action. As previously mentioned, due to the positioning ofseals 105 and 106 a lower pressure is generally applied to seal 106 thanthat used in inflating seals 105 and 122. Accordingly, as shown inFigure 6, solenoid SC when energized operates its 3-way valve to admitthe desired inflating pressure to seal 1% and likewise solenoid SD whenenergized admits a somewhat higher pressure to inflate seals 105 and122.

As pneumatic actuator 57 closes the shroud door 52 as a result of theenergization of solenoids SA and SB, such door, by means of arm 55,closes the door switch contacts DS. Contacts DS are connected in seriewith the operating coil of a relay RB through a lead 152 extendingthrough the normally closed contacts of stop button 151 and weightswitch contacts WS. One pair of contacts RB]. of relay RB are connectedin shunt with relation to contacts DS to form a holding circuit forrelay RE. A second set of contacts RBz of relay RB serve to set up acircuit extending through contacts WS for energization of solenoidscontrolling the vacuum valve, relief valve and material supply valve ofthe filling machine.

In addition to energizing relay RB, the closing of the door switchcontacts DS effects energization of a timer 155. This timer is set toenergize the coil of a solenoid SE for a predetermined period of time,in the order of two or three seconds, after which such solenoid isdeenergized. Solenoid SE is coupled to a 3-way valve which is effectiveto operate the vent valve 134 so as to admit alternatively pressurizedfluid or vacuum to the diaphragm of valve 134- to either close oropen'such valve. As shown in Figure 6, pressure is communicated to thevalve 134 with solenoid SE de-energized. Upon energization of solenoidSE, the 3-way valve is actuated to communicate vacuum to the vent valveso as to open such valve for the period of energization of the solenoidSE, after which time valve 134 is closed by pressure again being appliedto its diaphragm.

Contacts RBa of relay RB are closed upon energization of such relay tostart a timer 16 The timer 16% connected in series with contacts RB:across the power source is operable to efiect intermittent energizationof a relay RC. The timer 160 maybe of any suitable. con: structionalthough preferably, for reliability and rapid operation, an electronictimer is used. As shown at 161, the timer is provided with a dial andpointer which may be adjusted as desired to vary the" interval of timeduring which relay RC is energized. The purpose and function of varyingor controlling the interval of relay RC energization will be moreapparent with reference to the stated operation of the invention as setforth hereinafter.

The contacts RCrof relay RC are connected in series with contacts R82and upon the closing of contacts RC1 after contacts RBzhave been closed,solenoids SF and SG are energized through the weight switch contacts WS.Solenoid SF operates a 3-way valve which controls the opening andclosing of the vacuum valve and solenoid SG acit'lates E1 3-way valveWhich in tliiil Controls the opening and closing of relief "valve 90. Intheir deenergized state, as shown in Figure 6, thevacuum valve 95 willbe closed by the admission of pressurized fluid to the diaphragm of suchvalve. At the same time the relief valve 90 is open by reason of avacuum or low pressure being communicated with its diaphragm. Uponenergization of solenoids SFand SG the vacuum valve is opened and therelief valve closed.

In addition to energizing solenoids SF and SG, upon closing of contactsRC1 a circuit is set up leading to a vacuum control 165. Vacuum control165 includes a pressure responsive switch, the contacts of which closein response to the vacuum existent within the shroud. With the shrouddoor closed, the vacuum valve open and the relief 'valve closed, thepressure within the shroud will diminish. Initially, the bag positionedon the filling spout within the shroud will be opened with air beingadmitted to the bag interior by reason of the opening of vent valve 134through the energization of solenoid SE. However, solenoid SE onlyremains energized for the relatively short period of, for example, 2 or3 seconds, asdetermined by the setting of timer and upon deenergizationof solenoid SE and closing of the vent valve, the vacuum within theshroud tends to increase. The vacuum control is set to close itscontacts upon the shroud vacuum reaching a predetermined point. Whensuch low pressure or vacuumobtains within the shroud, the vacuum controlcontacts close to complete the circuit through the coil of a relay RD.

Contacts RDI of relay RD close to set up-a holding circuit bypassing thevacuum control 165. The provision of contacts RDl shunting the contactsof the vacuum control 165 has been found to be desirable to preventintermittent opening and closing of relay RD. This action, in theabsence of holding contacts RDi might occur upon opening of the materialsupply valve accompanied by a drop in the shroud vacuum which in turnwould cause a response in the vacuum control 165 resulting in opening ofits contacts thereby de-energizing relay RD and closing the materialsupply valve until the shroud vacuum builds back up to operate thevacuum control.

A second set of contacts RDz are likewise closed upon energization ofrelay RD at which time a solenoid SH is energized. Solenoid SH iscoupled to actuate a 3- way valve which controls the opening and closingof the material supply valve 133. Preferably, material valve 133operates after about a 2-second delay following the obtaining of thevacuum within the shroud for which control 165 is set. This permits thepressure within the shroud and bag interior to stabilize beforeadmitting material into the bag. As shown on Figure 6 with solenoid SHde-energized, pressure is admitted to the diaphragm of valve 133 tomaintain it closed. Upon energtzation of solenoid SH, vacum is admittedto the diaphragm of valve 133 to open such valve for the admission ofmaterial from the supply hopper into the bag'to be filled through thefilling spout.

Referring again to timer 160, it has been stated that 9 this timerfunctions to intermittently energize relay RC, Thus, it will be seenthat each time relay RC is energized, closing its contacts RC1, thevacuum valve will open, the relief valve close and, when the vacuumwithin the shroud becomes sutficient to actuate the vacuum control 165,the material valve will open. Likewise, when relay RC is de-energized,under the control of timer 160, the vacuum valve will close, the reliefvalve open and the material supply valve close.

When the desired weight of material in the form of successive incrementsof material has been discharged into the bag retained within the shroud,the scale mechanism 13 will respond, resulting in its pin 27 actuatingthe weightswitch. Thereupon, the weight switch contacts WS will open,de-energizing the various relays and solenoids in the control circuitand returning the apparatus, upon the opening of contacts RAr, to astatus in readiness for the next succeeding bag filling cycle. The nextbag filling operation may be commenced after the filled bag is removedand an empty bag placed in the shroud on the filling spout.

By appropriately setting the timer 160, the size of the material fillincrements may be fixed. Thus, if a relatively large number ofincrements are to be dispensed to completely fill the bag, the timer 160will be set to eifect energization of relay RC for a shorter period thanif larger and fewer material increments are desired to complete the bagfilling. It will likewise be appreciated that the degree of vacuum usedin operating the filling machine will determine to some extent thequantity of material drawn into the bag for a given time interval ofenergization of relay RC.

The interval of time between successive actuations of relay RC willdetermine the period during which the relief valve is opened andtherefore the extent to which the vacuum within the shroud isdiminished. It is critically important in connection with the instantinvention that the relief valve does not remain open to return theshroud pressure to atmospheric between fill increments. If such ispermitted in filling bags wih finely powdered material the inrush of airand pressure increase tends to fluff up the powdered material, producinga result directly contrary to the desired objective of compacting thematerial and withdrawing air entrained between the particles of thepowdered material. Accordingly, the relay RC is only momentarilyde-energized between filling increments so that the relief valve willonly open for an instant to diminish the shroud pressure withoutreturning it to atmospheric. To give specific figures, merely by way ofexample, the relief valve will open only for one-half second or less todrop the shroud pressure around inches of mercury. Thus, where 20 inchesof mercury vacuum is being used in the filling operation, so that thisdegree of vacuum exists within the shroud to draw the material into thebag, the relief valve will open momentarily to drop the shroud pressureto about 15 inches of mercury between each fill increment. This suddenpressure increase after each increment of material is discharged intothe bag causes a reverse flow of air through the interstices of the bagwall to clean the bag and momentarily wrinkle the wall to free it ofpowder which accumulates as air is withdrawn through the porous bagduring introduction of powderedmaterial. At the same time, there iscontinuously maintained a vacuum above the material tending to withdrawentrainedair from the powdered material mass within the bag. Theexistence of the vacuum promotes compacting of the material while thebag wall pores are cleaned of powder preparatory to receiving the nextincrement of fil i The degree of compacting achieved by utilization ofthe principles of the herein disclosed invention may be varied inseveral ways. First, if a high degree of final product density in thereceptacle is desired, a greater number of smaller size increments maybe combined to complete the filling of the receptacle than would be usedif a lower density product is wanted. Secondly, the degree' of vacuumused in the filling operation may be se lected to secure the desiredcompacting or density of product from the filling operation. Thus, wherea high vacuum is employed, the filled receptacle will have a higherdensity of their fill than where a lower vacuum is used in the fillingoperation. Also, in connection with filling machines, the final fillproduct density may be altered by changing the orifice characteristicsof the filling spout.

With regard to the vacuum preferably used in the filling operations, arange of from 4 inches to 28 inches of mercury may be employed dependingto some extent on the specific material being handled. With most finelydivided powdered materials a vacuum of from 22 inches to 25 inches hasbeen found to be ideal. However, as a specific example, in filling withcarbon black a vacuum of 18 inches has proved desirable, since at highervacuums undue compacting and caking of the carbon black material mayoccur.

The overall operation of the apparatus will be understood with referenceto the description of the schematic diagram of Fig. 6. By way of generalsummary, however, a brief review of the operations that take place willbe given. Assuming that an empty bag, usually in a flattened condition,has been placed in the shroud with the filling spout extending into themouth of the bag, the start button is pressed to initiate the automaticfilling cycle. This action energizes relay RA which closes a relayholding circuit through contacts RA1 and through contacts RAz energizessolenoids to eifect closing of the shroud door and inflation of thevarious filling spout seals to retain the bag on the spout. The closingof the shroud door closes contacts DS which results in energizing relayRB and timer 155. Timer energizes the vent valve solenoid to maintainsuch vent valve open for a relatively short period to admit air to openthe bag prior to commencing introducing the fill material.

Relay RB through its contacts RBa starts operation of timer whichintermittently energizes relay RC. Contacts RC1 of relay RC completewith contacts RBz the circuit to solenoids SF and SG which controloperation respectively of the vacuum valve and the relief valve.Contacts RC1 also set up a circuit to the pressure responsive vacuumcontrol 165, which control closes its con tacts when the shroud pressurereaches the desired degree of vacuum. ,Upon closure of the vacuumcontrol contacts, which takes place after the vent valve has admittedbag opening air to the bag and thereafter closed to permit build-up ofthe vacuum within the shroud, relay RD is energized. Contacts RD1 ofthis latter relay close a holding circuit around the vacuum control andcontacts RDz of relay RD complete a circuit for energization of solenoidSH. Solenoid SH effects opening of the material valve which preferablytakes place about 2 seconds after the vacuum controlhas responded toshroud vacuum, permitting material to flow into the bag under theinfluence of vacuum present within the shroud and bag. It may be notedhere that the vacuum within the shroud exists to generally the samedegree within the bag by reason of seepage of air through the perviouswalls of the bag.

Each time relay RC is de-encrgized under control of timer 160 the flowof material will be termined by closing of the material valve and thevacuum within the shroud diminished'by momentary opening of the reliefvalve with the vacuum valve closed. When timer 160 re-energizes relayRC, the sequence of operations of the relief valve, vacuum valve andmaterial valve repeats. Such repeti tion for incremental'filling of thebag continues until the scale mechanism responds to a full material loadwithin the bag. At the occurrence of this, the contacts WS arejopened bythe scale mechanism and the circuits to the various control relays andsolenoids de-energized;

De-energization of solenoids SA and SB causes actuator 57 to open theshroud door while de-energization of solenoids SC and SD causesdeflation of the filling spout seals to release the bag from the fillingspout.

Having thus described my invention, whatI claim iszi 1. A method offilling a receptacle with finely divided particulate material whichcomprises creating a vacuum within the receptacle to befilledpad'rfiitting' material into the interior of said receptacle,terminating the admission of material after only an increment of thequantity of material required to fill the receptacle hasbee'irdispen'sed into the receptacle, momentarily diminishing the vacuumwithin the receptacle to cause an instantaneous reverse flow of air backinto the receptacle while continuously maintaining a substantialsub-atmospheric pressure within the receptacle to withdraw air frombetween the material particles to compact the material, and repeatingthe above recited steps until the increments of material fill thereceptacle to the desired degree.

2. A method of filling a receptacle with finely divided particulatematerial which comprises creating a vacuum within the receptacle to befilled, admitting an increment of material into the receptacle under theeffect of the vacuum within the receptacle, terminating the flow ofmaterial into the receptacle, momentarily diminishing the vacuum withinthe receptacle While continuously maintaining a substantialsub-atmospheric pressure within the receptacle to withdraw air frombetween the material particles to compact the material, and repeatingthe above-recited steps until the increments of material fill thereceptacle to the desired degree.

3. A method of filling a collapsible receptacle with finely dividedparticulate material which comprises creating a vacuum within andsurrounding the receptacle to be filled, admitting gaseous fluid intothe interior of the receptacle to expand same to its fully openedcondition, discharging an increment of material into the receptaclewhile the vacuum is maintained within the receptacle, terminating theflow of material into the receptacle, momentarily diminishing the vacuumwithin the receptacle while continuously maintaining a substantialsub-atmospheric pressure within the receptacle to withdraw air frombetween the material particles to compact the material, repeating thethird, fourth and fifth steps recited above to dispense a series ofincrements of material into the receptacle, and terminating therepetition of the third, fourth and fifth steps when a predeterminedweight of material has been dispensed into the receptacle.

4. In a bag filling machine, a shroud providing a chamher for receivinga bag during the filling thereof and having an access door to permitintroduction and removal of the bags being filled, a scale mechanismsupporting said shroud whereby said mechanism will indi cate the weightof material dispensed into thebag within the shroud, a feed spoutcarried by said shroud with the outlet end thereof disposed within saidshroud for insertion into the mouth of a valve type bag, a seal elementencircling said feed spout adjacent the entrance of said spout into saidshroud and adapted to be actuated to retain the valve bag on said spoutwithin said shroud and preclude escape of material from the bag intosaid shroud, a material supply hopper, a material supply conduitconnecting said feed spout and said material hopper and having a valveinterposed therein actuatable to control the flow of material from thehopper to said feed spout, a second valve operable to control admissionof a gaseous fluid through said spout and into the bag to effect openingof the bag retained on said spout, and means for applying a vacuum tothe interior of said shroud to draw material from said hopper into thebag retained on said spout. t

5. In a bag filling machine as recited in claim 4 wherein said sealelement includes an expandable resilient member having an interior spacewhichmay be siibje cted' 12 to fluid pressure to expand said member intoengagement with the mouth of the bag to be filled.

6. In a bag filling machine as recited in claim 4 wherein pairs ofparallel members are provided adjacent the top and bottominterior ofsaid shroud with one of each of said pairs of members being mounted onand mov able with said access door whereby upon opening of said doorsaid pairs of members will be moved apart to facilitate positioning ofthe upper and lower bag seams to be disposed. between the members onclosing of the access door. v

7. In a bag filling machine as recited in claim 6 where in the interiorsurfaces of the chamber of said shroud and the surfaces of the seammembers exposed to the shroud interior are grooved to promoteapplication of vacuum to the entire exterior surface of the bag beingfilled.

8. In a bag filling machine as recited in claim 4 wherein an annularcavity is provided surrounding the feed spout adjacent its point ofentry into said shroud, and said seal element encircling the feed spoutis disposed within said cavity to clamp the mouth of thevalve bagbetween the periphery of said feed spout and the wall of said cavity.

9. In a bag filling machine as recited in claim 8 wherein an upstandingpocket communicating at its lower end with said annular cavity isprovided adjacent the point of entry of said feed spout into saidshroud, and an expandable seal element extends around the top and sidesof said pocket to clampingly retain the upper bag's'eam within saidpocket.

10. In a bag filling machine as recited in claim 8 further having anexpandable seal embedded in the periphery of the outer end of said spoutto function when expanded as a preliminary seal in retaining the valvebag on the spout.

11. In a bag filling machine, a supporting frame, a scale mechanismsuspended from said supporting frame consisting of a primary scale beamfulcrurried adjacent one end thereof, a secondary scale beam fulcrumedintermediate the ends thereof and overlying said primary scale beam,means interconnecting the opposite end of said primary beam and one endof said secondary beam for transmission of forces between said beams,the opposite end of said secondary scale beam having a counter weightadjustable to alter the response of the scale mechanism, a shroudsuspended from a point intermediate the ends of said primary scale beamand providing a chamber for receiving a bag during the filling thereofwith an access door to permit introduction and removal of the bags beingfilled, a feed spout carried by said shroud with the outlet end thereofdisposed within said shroud forinsertion into the mouth of a valve typebag, a seal element encircling said feed spout adjacent the entrance ofsaid spout into said shroud and adapted to be actuated to clampinglyretain the valve bag on said spout within said shroud, a materialhopper, a material supply conduit connecting said feed spout and saidmaterial hopper and having a valve disposed therein actuatable tocontrol the flow of material from the hopper to said feed spout, a ventvalve operable to'control admission of a gaseous fluid through saidspout and into the bag to effect opening of the bag clamped on saidSpout, and means for applying a vacuum to the interior of said shroud todraw material from said hopper into the bag clamped on said spout.

12. In a bag filling machine as recited in claim 11 further having adash pot device connected to said opposite end of said secondary scalebeam to retard movements of'suc h beam during filling of the bagretained within said shroud. I V

13. Ina bag' filling machine as r ecitedin claim 11 wherein said shroudis yieldably connected said frame to restrict lateral movement of saidshroud relative to said frame while permitting limited vertical movementof said shroud as said scale mechanism responds to the introduction ofmaterial into the bag being filled.

14. In a bag filling machine as recited in claim 11 wherein means isprovided adjacent said opposite end of said secondary scale beamoperative in response to movements of such end to terminate the bagfilling operation when the desired weight of material has been dispensedinto the bag within the shroud.

15. In a bag filling machine, a shroud providing a chamber for receivinga bag during the filling thereof and having an access door to permitintroduction and removal of the bags being filled, switch means mountedto have the contacts thereof closed upon closing of said access door, ascale mechanism supporting said shroud and having means operable uponintroduction of the desired weight of material into bag being filled toterminate the filling operation, a feed spout disposed within the upperend of said shroud and having a seal element actuatable to engage withthe mouth of the bag being filled to retain same on said spout, amaterial supply hopper, a material supply conduit interconnecting saidfeed spout and said hopper and having a material valve interposedtherein actuatable to control the flow of material through said feedspout, a vent valve operable to control admission ,of a gaseous fluidthrough said spout and into the bag to effect opening of the bagretained on said spout, a vacuum valve for coupling the interior of saidshroud with a source of vacuum, a relief valve for communicating theinterior of said shroud with atmospheric pressure, means operable uponclosing of said switch means to open said vent valve for a predeterminedtime period, timer means actuated upon closing of said switch means toclose said relief valve and open said vacuum valve and after apredetermined time interval to open said relief valve and close saidvacuum valve, and pressure responsive means connected to open saidmaterial valve when the pressure within said shroud reaches apredetermined vacuum.

16. In a bag filling machine as recited in claim 15 further having afluid driven actuator connected to effect opening and closing of saidaccess door, and means for selectively controlling flow of pressurizedfluid to said actuator to open and close said doom.

References Cited in the file of this patent UNITED STATES PATENTS1,037,824 Fasting Sept. 3, 1912 2,060,011 Andreas Nov. 10, 19362,181,756 Cook Nov. 4, 1939 2,232,437 Bushman Feb. 18, 1941 2,513,143Carter June 27, 1950 2,531,743 Ray Nov. 28, 1950 2,613,864 Carter Oct.14, 1952 2,650,058 Read Aug. 25, 1953 2,718,345 Howard Sept. 20, 1955

